The Dog Days of Summer are rapidly moving toward fall, but owners of dogs and other pets need to remain vigilant about the risks of blue-green algae on lakes and wetlands.

So says Jim Collins Jr., an environmental scientist in the Water Quality Division of the North Dakota Department of Environmental Quality in Bismarck.

Triggered by excess nutrients from ag or urban runoff, blue-green algae tends to be a late-summer problem as water temperatures rise, especially in lakes and wetlands with little flowing water. The cyanotoxins produced by blue-green algae can be fatal to pets and livestock and pose serious health risks to humans, Collins says.

Hunters training dogs in advance of waterfowl and other hunting seasons need to be especially careful around lakes or wetlands when in the field this time of year, especially if the water looks like pea soup-colored paint or smells bad.

Dogs that drink or even swim in water contaminated with blue-green algae can suffer neurological and liver damage; the risks need to be taken seriously.

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“It does have some serious effects, especially for pets,” Collins said. “Dogs can die within 25 to 30 minutes, and there’s really not a lot you can do because there’s no antidote.”

Brad Dokken
Brad Dokken

Carrying fresh water can lessen the temptation for dogs to head toward scummy-looking water for a drink or a bath, but avoiding areas with known algae blooms is the safest option.

Collins’ advice: Take a look at the water and check out the latest warnings and advisories on the Department of Environmental Quality’s website, which includes a map updated daily listing bodies of water where advisories or warnings are in effect and pictures of blue-green algae and how it looks in the water.

“Every year, there are some hunters that unfortunately lose their prize dog to getting into a wetland with blue-green algae,” Collins said. “It’s heartbreaking when that happens.”

As of midweek, warnings were in place for six lakes across North Dakota, including Stump Lake in Nelson County and South Golden Lake in Steele County. Devils Lake, Wood Lake in Benson County, Homme Dam in Walsh County and Renwick Dam in Pembina County were among 14 lakes across the state with advisories in effect.

Lakes with toxin levels high enough to warrant warnings are sampled weekly, Collins says, and lakes where advisories are in effect are sampled every two weeks.

There have been more reports of blue-green algae in North Dakota this summer, he says, perhaps because people are becoming more aware of the problems it can cause. Last year, the department sampled about 19 lakes, compared with 34 or 35 this year, Collins says.

“We’ve gotten a lot more reports from the public, which is how we actually find out about them,” he said. “There are over 400 managed lakes in the state and we have limited staff so to get to all of them is not possible. So, we really rely on the public to say, ‘Hey, we were at this lake and it’s green. Can you come out and check?’

“You can’t go by just looking at the water; you actually have to get out and sample it.”

So far this summer, there have been a few health effects, Collins says, including rashes and blistering among people who came into contact with the algae.

“We haven’t seen anything worse than that in humans,” he said. “A few cattle deaths this year from cattle that have gotten into a lake or a pond that’s had blue-green algae on it and died.”

There haven’t been any confirmed pet deaths, but there have been at least two cases of dogs dying where blue-green algae was the suspected cause.

Typically, the risks subside in October as water temperatures cool, but for now, Collins recommends people be vigilant.

“If you get into an area where there’s a bloom, you definitely want to take care,” he said.